How can I make a JInternalFrame not display its contents when being dragged?

Here is a snippet from the Swing tutorial. I think
it only works for Metal/JFC look and feel -

In a future release, the Swing team plans to add a method to let you specify outline dragging. Until that method is added, you can specify outline dragging by setting a client property of the desktop pane, like this:

desktop.putClientProperty("JDesktopPane.dragMode",
"outline");

The preceding code has no effect in JFC implementations before Swing 1.1.1 Beta 1.